Date: Sun, 31 Mar 2002 09:16:18 -0600 (CST) From: Mike Silbersack <silby@silby.com> To: Leo Bicknell <bicknell@ufp.org> Cc: Paul Halliday <dp@penix.org>, <hackers@FreeBSD.ORG> Subject: Re: GPS time. Message-ID: <20020331091304.U40871-100000@patrocles.silby.com> In-Reply-To: <20020330142859.GA19243@ussenterprise.ufp.org>
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On Sat, 30 Mar 2002, Leo Bicknell wrote: > Your NTP servers are better. > > I tested a III Plus, and without a 1 PPS source (which that model > doesn't provide) it's accurate to about 100ms, give or take. Since > real NTP servers are < 1ms, they really aren't that good. It's > not that the time isn't accurate, it's that they were not designed > to communicate with that accuracy to an external device. OTOH, 100ms is pretty close; I doubt many people need time better than that. The one big advantage I can see with using a GPS receiver vs NTP servers is security & reliability; I've always worried that my clock might start to drift to a misconfigured NTP server. Taken to a paranoid level, you could worry that someone was faking NTP replies to throw your clocks off. :) So, even at 100ms accuracy, it might be better to use a local GPS unit. <shrug> Mike "Silby" Silbersack To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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